1. Field of the Invention
The present invention relates generally to an electrical connecting technology, more particularly, a method for fabricating a microconnector and the shape of terminals of the microconnector.
2. Description of the Background Art
Generally, the function of a connector is to provide a separable interface for connecting subsystems in an electronic system, so as to transmit signal and/or electric power. Connectors have been employed for a long time, the number of related patents and technology are vast, e.g., U.S. Pat. Nos. 4,176,900; 4,330,163; 4,630,874; 4,636,021; 4,684,194; 5,092,789; 5,172,050 and 6,817,776, Taiwan Laid-Open Patent for Invention No. 595826, Taiwan Utility Model Certificate No. M260896 and the like.
In order to maintain stability of the contacting interface during operation of the electronic system, conventional connectors produce normal contact force at the contacting interface. However, due to more and more pins are designed on the connectors of the integrated circuit and the printed circuit boards, high insertion force may be produced during assembling in U.S. Pat. No. 4,176,900, for example. Furthermore, in order to reduce the insertion force, the normal contact force often must be sacrificed; but, when the normal contact force is insufficient, contact resistance increases, causing more signal attenuation. Accordingly, a connector with zero insertion force is proposed in U.S. Pat. No. 5,092,789, for example.
U.S. Pat. No. 5,092,789 provides a beam connected between a lid member and a base member that is pressed after insertion of a CPU, so that the lid member translates forward with respect to the base member, causing the slot of the base member to latch on the pins of the CPU to provide normal force. Such connector can solve the contradiction of the previous technology that concurrently requires high normal contact force and lower insertion force, but due to limitations of the traditional mechanical mold fabrication and metallic terminal stamping technique, the minimum interval between the terminals that can be made is about 0.3 mm, and cannot be diminished further.
In order to address the issue of further minimization of connectors limited by traditional fabricating method, Michael P. Larsson and Richard R. A. Syms et al. had proposed a self-aligning micro-electro-mechanical system (MEMS) in-line separable electrical connector in pages 365 to 376 of Chapter 2 in Part 13 of the Journal of Microelectromechanical Systems published in April, 2004. In contrast to those connectors fabricated with the above traditional technology, this connector is fabricated by the microelectromechanical fabricating process, and it has a self-aligning mechanical structure.
However, friction may be produced when the male terminals are inserted into the female terminals of the above connector; it not only degrades the integrity of signal transmission, but is also adverse to the design of multi-terminal connector. Simultaneously, without the design for impedance matching, such conventional connector affects the bandwidth of signal transmission. In addition, the connector fabricated by the technology does not take into account of shielding EMI (electromagnetic interference), which results in the phenomenon of noise produced between devices interfering with the normal operation of other devices. Furthermore, such conventional connector does not propose a suitable latchable mechanism, it may result in situations that the male terminals cannot be properly inserted into the female terminals or has poor contact after insertion. Accordingly, such conventional connector is yet to be improved.
Furthermore, the conventional MEMS component must firstly go through a fabricating process of wire bonding or solder ball bonding in order to be connected to testing apparatus for functional tests, i.e., each time the component is tested it must be encapsulated through wire bonding or solder ball bonding, such that the component cannot be reworked, and the related testing apparatus cannot be used again, which is a waste of time and cost. In addition, most of the above conventional techniques results in high insertion force, which will quickly wear out the terminals. Furthermore, thermal effect produced at high temperature during the MEMS fabricating process may cause the female terminals to curve downwards when the sacrificial layer is released, such that electrical signals cannot be successfully transmitted when the male terminals are inserted into the female terminals; or cause the female terminals to curve upwards, so that they encounter “kinking effect” when the male terminals are inserted thereto.
Accordingly, there exists a strong need in the art to solve the drawbacks of the above-described conventional technology, such as high insertion force, overlarge size, lack of impedance matching, electromagnetic interference shielding and latchable mechanism and is unfavorable to multi-terminal connector design.